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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 4 |
| 3 | -1216 |
| 4 | 2310400 |
| 5 | -13094125568 |
| 6 | 41787366322733056 |
| 7 | 609452979875950622670848 |
| 8 | 150142808011575068721319772160000 |
| 9 | -7129771654003819760990676428837143372103680 |
| 10 | 114629197516562460020595757143135575237521247385419776 |
[2,4,-1216,2310400,-13094125568,41787366322733056, 609452979875950622670848, 150142808011575068721319772160000, -7129771654003819760990676428837143372103680, 11462919751656246002059575714313557523752124738541\ 9776] |